U.S. Pat. No. 6,130,300 issued Oct. 10, 2000 to Jaber discloses a low aluminum and magnesium Ziegler-Natta system. The catalyst comprises a mixture of an aluminum alkyl compound and a dialkyl magnesium compound, an alkyl halide, a titanium halide and a dialkyl aluminum alkoxide. The patent does not suggest that a silanol could be used in the catalyst. Additionally, the present invention contemplates some cases where the dialkyl aluminum alkoxide is absent.
U.S. Pat. No. 4,295,992 issued Oct. 20, 1981 to Gibbs teaches preparing a catalyst support by reacting an alcohol, an organo magnesium compound and a silicon halide. The present invention has eliminated the essential alcohol from the teaching of U.S. Pat. No. 4,295,992.
U.S. Pat. No. 4,612,300 issued Sep. 16, 1986 to Coleman, III teaches a Ziegler Natta catalyst in which one component is a soluble organomagnesium component of the formula MgR″2.xMR″y in which M may be Al, Zn, Si, Sn, B or P. There is no significant teaching regarding the possible use of silicon containing compounds. Further the catalyst requires the presence of a vanadium compound which has been eliminated from the catalysts of the present invention.
The present invention seeks to provide a catalyst useful in high temperature solution polymerization.